Jaggedness in my rendered image in cycles rendering
These are antialiasing artifacts caused by low resolution and high contrast.
Renders in 4K/8K (or with lower contrast) are visibly less jagged.
Why:
A 2K render simply doesn't have enough pixels for antialiasing such a narrow and contrasty area.
8K Render - High Contrast (still a little bit jagged)
8K Render - Low Contrast (perfectly crisp edges)